The Endothelial E3 Ligase HECW2 Promotes Endothelial Cell Junctions by Increasing AMOTL1 Protein Stability via K63-linked Ubiquitination

Cell Signal. 2016 Nov;28(11):1642-51. doi: 10.1016/j.cellsig.2016.07.015. Epub 2016 Aug 4.

Abstract

Cell-to-cell junctions are critical for the formation of endothelial barriers, and its disorganization is required for sprouting angiogenesis. Members of the angiomotin (AMOT) family have emerged as key regulators in the control of endothelial cell (EC) junction stability and permeability. However, the underlying mechanism by which the AMOT family is regulated in ECs remains unclear. Here we report that HECW2, a novel EC ubiquitin E3 ligase, plays a critical role in stabilizing endothelial cell-to-cell junctions by regulating AMOT-like 1 (AMOTL1) stability. HECW2 physically interacts with AMOTL1 and enhances its stability via lysine 63-linked ubiquitination. HECW2 depletion in human ECs decreases AMOTL1 stability, loosening the cell-to-cell junctions and altering subcellular localization of yes-associated protein (YAP) from cytoplasm into the nucleus. Knockdown of HECW2 also results in increased angiogenic sprouting, and this effect is blocked by depletion of ANG-2, a potential target of YAP. These results demonstrate that HECW2 is a novel regulator of angiogenesis and provide new insights into the mechanisms coordinating junction stability and angiogenic activation in ECs.

Keywords: AMOTL1; EC junction; HECW2; Sprouting angiogenesis; YAP.

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Angiopoietin-2 / metabolism
  • Gene Deletion
  • Human Umbilical Vein Endothelial Cells / metabolism*
  • Humans
  • Intercellular Junctions / metabolism*
  • Lysine / metabolism*
  • Membrane Proteins / metabolism*
  • Neovascularization, Physiologic
  • Phosphoproteins / metabolism
  • Polyubiquitin / metabolism
  • Protein Binding
  • Protein Stability
  • Protein Transport
  • Transcription Factors
  • Ubiquitin-Protein Ligases / metabolism*
  • Ubiquitination*

Substances

  • AMOTL1 protein, human
  • Adaptor Proteins, Signal Transducing
  • Angiopoietin-2
  • Membrane Proteins
  • Phosphoproteins
  • Transcription Factors
  • YAP1 (Yes-associated) protein, human
  • Polyubiquitin
  • HECW2 protein, human
  • Ubiquitin-Protein Ligases
  • Lysine